Here's some simple code to parse your json without creating a proper class to represent its structure like Jon suggested. I might have misunderstood the exact structure of your json so here is the sample json I worked with, perhaps you will need to make small adjustments to it will fit your case:
{ 
  "rateDetails":[
    {
      "date":"19-9-2015",
      "allAdultFares":["0-5000.00","1-8000.00"],
      "Flag":"N"
    },
    {
      "date":"20-9-2015",
      "allAdultFares":["0-9000.00","1-9000.00"],
      "Flag":"N"
    }
  ]
}
I used JSon.Net to parse the file, you can get it from nuget.
        var input = JObject.Parse(File.ReadAllText("sample.json"));
        var rateDetails = (JArray)input["rateDetails"];
        var a = rateDetails
                    .Select(t => (JArray)t["allAdultFares"])
                    .Select(t => 
                        new Sellrate() 
                        { 
                          Singe = t[0].ToString().Split('-')[1].Replace(@"""", ""), 
                          Double = t[1].ToString().Split('-')[1].Replace(@"""", "") 
                        }).ToList();
     
    
List<string>property forallAdultFares, and astringproperty forFlag) and then convert that into yourSellRateclass later.